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Fishery Bulletin 90(4), 1992 



spicules were also visible over the entire body integu- 

 ment, except the pupil of the eye, by 4 mm. 



Body measurements were made on 30 cobia larvae 

 to examine developmental morphology (Table 1). Pre- 

 anal length was 61.5-62.5% SL in yolksac larvae and 

 increased slightly during preflexion, but decreased 

 steadily thereafter. A single intestinal loop, visible 

 through the body wall, gave the ventral visceral mass 

 a bulbous appearance by 7 mm. Body depth was about 

 20% SL in larvae < 10 mm but decreased to about 15% 

 by 25 mm. Likewise, orbit diameter decreased from 

 about 11-7%SL as larvae increased in length. Other 

 body proportions were relatively stable until larvae 

 were >10mm. Thereafter, a slow but steady decline 

 occurred in all proportions when compared with SL, 

 except caudal peduncle length which remained constant 

 (Table 1). The relationship between standard and total 

 lengths (TL), as defined by regression analysis, was 

 linear and highly correlated (SL = 0.73 TL-t- 1.44; N 29, 

 r2 0.998) at all sizes. 



The supraorbital ridge and two largest preoper- 

 cular spines were visible by 4 mm, and the pterotics 

 were laterally swollen. The two preopercular spines 

 were located on either side of the angle of the pos- 

 terior preopercle. Three smaller spines, the largest of 

 which was inserted between the two posterior preoper- 

 cular spines, were also present along the anterior 

 preopercle. Spines were added along both the anterior 

 and posterior preopercle until a total of 4 anterior 

 and 4-5 posterior preopercular spines was reached 

 by 14-15 mm. A single spine occurring along the 

 supraorbital ridge of each frontal bone by 4.5mm 

 was directed posterolaterally by 6 mm. The supra- 

 orbital spine and swollen pterotics were best observed 



when viewed dorsally (see Hardy 1978 for illustration). 

 A supracleithral spine also occurred about 10.5-11 

 mm, and two posttemporal spines (supratemporal of 

 Dawson 1971) originating from a common base were 

 visible by 12 mm. All head spination was simple and 

 unserrated. 



In early larvae, internal pigment on the roof of the 

 mouth and ventral to the hindbrain and otic capsule 

 formed a mediolateral stripe through the head. Exter- 

 nally, melanophores were scattered over the snout, 

 fore- and midbrains, on the nape, and over the oper- 

 culum. Pigment also occurred immediately anterior to 

 the cleithral symphysis and along the isthmus. Both the 

 tip of the quadrate bone and dentary remained unpig- 

 mented until 7-7.5 mm. Head pigmentation increased 

 with length (Fig. 2). Minute epithelial spicules (Johnson 

 1984) covered the body by 4 mm, but were best ob- 

 served on the head and larval finfold. Spicules were 

 more easily observed on the integument as larvae in- 

 creased in length. 



Along the dorsal midline, a bilateral row of melano- 

 phores extended posteriorly from the nape to above the 

 anus, behind which these rows coalesced to form a con- 

 tinuous band of postanal, dorsal pigment. By 4.5mm, 

 pigment occurred on the pectoral fin base, and larvae 

 were sparsely pigmented dorsolaterally but heavily 

 pigmented ventrolate rally. The caudal peduncle was 

 unpigmented in early larvae, but pigment extended 

 onto the peduncle by 5.5-6.5 mm and over the lower 

 hypural bones by 7mm. Pigment was also present on 

 the posterior third of the anal finfold and proximally 

 on the ventral caudal-fin rays by 7.5 mm. Body and 

 anal- and caudal-fin ray pigment increased with length. 

 Pigment occurred on the posterior dorsal-fin pteryio- 



